This invention relates to a billet scalper which is constructed independently or in combination with an extrusion press.
It is known in the art to employ a billet scalper which is arranged to remove black skins and segregated alloy layers from outer surfaces of cast billets by cooperation of a die assembly including a scalping die and a pressing member.
The billet scalping operation is indispensable to indirect extrusion presses to obtain products of good quality by improving the flow of billets, as well as to direct extrusion presses in which an especially high criterion is imposed on the quality of products as in the case of aeronautical parts. Therefore, there have been proposed various scalpers intended exclusively for independent scalping operation and scalper-built-in type extrusion presses.
No matter whether it is an independent billet scalper or an extrusion press with a built-in scalper, the recent concern over the scalping operation is how the chips should be handled without impairing the accuracy of scalping. Namely, the chips which are diversified in shape and relatively bulky are difficult to handle and, if the chips deposit on the scalping die, a difficulty is encountered in handling the succeeding billets, not to mention of efficient scalping and speed-up of the press cycle.
If a black skin or other foreign matter deposits on a scalping die, there arises a necessity for cleaning it off or for replacing the die. In this connection, the conventional fixed type die assembly which is mounted at the center of the machine makes the die cleaning or replacing work difficult and compels hard labor from stationed workers.